1. Field
The present disclosure pertains to the field of information processing, and more particularly, to the field of error detection and correction in information processing systems.
2. Description of Related Art
As improvements in integrated circuit manufacturing technologies continue to provide for greater levels of integration and lower operating voltages in microprocessors and other data processing apparatuses, makers and users of these devices are becoming increasingly concerned with the phenomenon of soft errors. Soft errors arise when alpha particles and high-energy neutrons strike integrated circuits and alter the charges stored on the circuit nodes. If the charge alteration is sufficiently large, the voltage on a node may be changed from a level that represents one logic state to a level that represents a different logic state, in which case the information stored on that node becomes corrupted. Generally, soft error rates increase as the level of integration increases, because the likelihood that a striking particle will hit a voltage node in a die increases when more circuitry is integrated into a single die. Likewise, as operating voltages decrease, the difference between the voltage levels that represent different logic states decreases, so less energy is needed to alter the logic states on circuit nodes and more soft errors arise.
Blocking certain types of particles that cause soft errors may be difficult, so data processing apparatuses often include support for detecting, and sometimes correcting, soft errors. For example, storage elements for parity or error-correcting-code (ECC) values may be added to information storage structures. However, the addition of these storage elements increases the size of the storage structure, and the increase in size is typically proportional to the level of detection/correction provided.